Caution for readers: The following is a discussion point and is neither a theory nor a speculation.
I am sure that we will hear more after the results of the news conference which was supposed to be held Wednesday afternoon in Hong Kong, are made available.
CONF iture;
Does it mean ENG 1 could not be shut down trough ENG MASTER ... and maybe relighted as soon after ... could it be possibly just another temporary computer whim ?
Well, computers don't have 'whims' but "what's it doing now?" is a familiar phrase... ;-)
I've been looking through some manuals. For the A320, do you recall an
ENG THR LEVER FAULT QRH procedure? The same procedure is in the A330 QRH. From what has been released thus far, it seems that one engine was shut down and the other was stuck at an setting between IDLE and CLB. While there seems little in common between the A330 event and this fault it is the closest fault I can find on a quick inspection. There is another fault, ENG 1(2) EPR MODE FAULT, which requires the use of manual thrust but does not require an engine shutdown.
I think the software has long since been modified but one time this fault required an autoland with autothrust engaged so that the autoflight system could control the engine thrust. The QRH alternative was to shut the engine down. There are various thrust levels at which the engine is 'stuck' depending upon ground or flight, slats extended or retracted, thrust lever position, (TOGA, FLEX/MCT, CLB or somewhere between CLB and IDLE).
In the current QRH procedure, the autothrust is left engaged and it is stated that FADEC will control the engine thrust but in this case it seems that this was not possible and that apparently the only option was to shut the remaining engine down once the field was assured.
PJ2